Direct-current circuit breakers that interrupt a direct current create a current zero point by superimposing a resonance current from a resonance circuit composed of a capacitor and a reactor and thus interrupt the direct current at the current zero point. Examples of conventional direct-current circuit breakers include the direct-current circuit breaker disclosed in Patent Literature 1. The direct-current circuit breaker disclosed in Patent Literature 1 includes a charging circuit that is used for charging the capacitor of the resonance circuit described above and that is composed of an alternating-current power supply and a rectifier, and the capacitor is pre-charged by the charging circuit. If a fault occurs, the charge accumulated in the capacitor is discharged and thus the resonance current is superimposed on the direct current so as to create a current zero point.